diff --git a/arch/alpha/isa/decoder.isa b/arch/alpha/isa/decoder.isa
index 905ace4e1..ac9f9fc4c 100644
--- a/arch/alpha/isa/decoder.isa
+++ b/arch/alpha/isa/decoder.isa
@@ -73,7 +73,9 @@ decode OPCODE default Unknown::unknown() {
                         uint64_t tmp = write_result;
                         // see stq_c
                         Ra = (tmp == 0 || tmp == 1) ? tmp : Ra;
-                    }}, mem_flags = LOCKED, inst_flags = IsNonSpeculative);
+                    }}, mem_flags = LOCKED, inst_flags = [IsNonSpeculative,
+                                                          IsSerializing,
+                                                          IsSerializeAfter]);
         0x2f: stq_c({{ Mem.uq = Ra; }},
                     {{
                         uint64_t tmp = write_result;
@@ -85,7 +87,9 @@ decode OPCODE default Unknown::unknown() {
                         // mailbox access, and we don't update the
                         // result register at all.
                         Ra = (tmp == 0 || tmp == 1) ? tmp : Ra;
-                    }}, mem_flags = LOCKED, inst_flags = IsNonSpeculative);
+                    }}, mem_flags = LOCKED, inst_flags = [IsNonSpeculative,
+                                                          IsSerializing,
+                                                          IsSerializeAfter]);
     }
 
     format IntegerOperate {
@@ -623,7 +627,7 @@ decode OPCODE default Unknown::unknown() {
 #else
                 Ra = curTick;
 #endif
-            }}, IsNonSpeculative);
+            }}, IsUnverifiable);
 
             // All of the barrier instructions below do nothing in
             // their execute() methods (hence the empty code blocks).
diff --git a/cpu/static_inst.hh b/cpu/static_inst.hh
index 550609ed7..0b8fe2f18 100644
--- a/cpu/static_inst.hh
+++ b/cpu/static_inst.hh
@@ -51,6 +51,7 @@ class AlphaDynInst;
 template <class Impl>
 class OzoneDynInst;
 
+class CheckerCPU;
 class FastCPU;
 class SimpleCPU;
 class InorderCPU;
@@ -128,6 +129,8 @@ class StaticInstBase : public RefCounted
         IsNonSpeculative, ///< Should not be executed speculatively
         IsQuiesce,
 
+        IsUnverifiable,
+
         NumFlags
     };
 
@@ -215,6 +218,7 @@ class StaticInstBase : public RefCounted
     bool isWriteBarrier() const { return flags[IsWriteBarrier]; }
     bool isNonSpeculative() const { return flags[IsNonSpeculative]; }
     bool isQuiesce() const { return flags[IsQuiesce]; }
+    bool isUnverifiable() const { return flags[IsUnverifiable]; }
     //@}
 
     /// Operation class.  Used to select appropriate function unit in issue.